Vacuum cleaner adapter for micro tools

ABSTRACT

A vacuum cleaner adaptor for micro tools consisting of an adaptor body of tubular form having a large diameter section for fitting to a conventional vacuum cleaner vacuum intake port or positive air pressure discharge port, an integral conical transition section and a small diameter section for fitting to a small diameter hose or tube or to the micro tool per se. In one form, longitudinal slots of arcuate configuration are formed within the conical transition section of the adaptor body at circumferentially spaced positions and are selectively closed off by a rotatable conical form shield having similar sized longitudinal slots therein. Radially projecting members on the shield and adaptor body limit rotation of the shield relative to the body between a full slot open position and a slot partially open position by circumferentially offsetting the slots of the adaptor body and shield. In a further embodiment, oblique holes are formed within the adaptor body large diameter section, oblique to the longitudinal axis of the tubular body. A sector shaped solid shield is rotatably mounted on the body for closing off given oblique holes to reduce air flow through the oblique holes as desired while ensuring sufficient air flow for preventing overheating of the vacuum cleaner motor of air cooled or air passed type.

FIELD OF THE INVENTION

This invention relates to a coupling tube adapter for connecting smalldiameter positive air pressure or vacuum operated tools to the suctioninlet or air discharge port or tube of a vacuum cleaner for access totight spaces such as cleaning typewriters and the like, and moreparticularly, to such coupling tube adapter which insures sufficient airflow to the vacuum cleaner to prevent overheating of the vacuum cleanermotor.

BACKGROUND OF THE INVENTION

Conventional vacuum cleaners employ air cooled or air pass throughmotors for preventing overheating of the vacuum cleaner motor duringoperation. For operation of small diameter vacuum pressure or positiveair pressure driven tools for access to tight spaces, a connection tubeassembly or adapter includes a large diameter tube section forattachment to the suction or positive air pressure sides of the vacuumcleaner and a much smaller diameter tube sized to the tool and coupleddirectly thereto or via a similar sized hose.

Domestic vacuum cleaners sold in the marketplace come in differentforms, namely upright, canister, combination canister with uprightfeatures of a revolving brush, stick types, hand vacs, shop vacs andbattery operated miniature vacs.

Vacuum cleaners, with the exception of the battery operated miniaturevacs, use conventional size attachments to either the vacuum side of the(air intake) vacuum cleaner or the positive air pressure discharge side.Generally speaking, the opening or orifice of the hose section coupledto the vacuum intake or air discharge side of the vacuum cleaner has a11/4 inch inside diameter. Such hose section diameter may vary slightly.The corresponding attachment to these hoses are normally of conventionalsize and type, for good reason. Air flow is very important. The insidediameter of the attachments permit enough air flow through theattachments to keep the vacuum motor from overheating during operationsince most domestic vacuum cleaners use air cooled (or air pass through)motors. Additionally, because the size of the debris being picked up bythe vacuum hose can vary to a large degree, a sufficiently large orificeis required to prevent clogging of the attachments. This relativelylarge size is also needed to deliver enough suction at the point wherethe attachment picks dust or debris.

Due to the shear size or bulkiness of the attachments, it is impossiblefor conventional domestic or commercial vacuum cleaners to clean smallconfined areas such as typewriter keys and the many parts involved incomputers and the like.

Miniature (tiny) battery operated vacuum cleaners are currently beingsold in the marketplace which have hoses whose diameters aresignificantly smaller and which claim capability of cleaning suchconfined areas. However, because of their very size, their usefulness interms of air flow is significantly limited. Further, because as batterylife decreases, so does the air flow, they are normally incapable ofproviding adequate air flow for an extended period of time. Attemptshave been made to meet the need by utilizing tubular attachments havinga large diameter section coupled directly to the vacuum cleaner, and asmaller diameter section integral therewith for attachment to thesmaller diameter too. Such adapters or coupling attachments are thesubject of the following U.S. patents:

    ______________________________________                                                 Issue                                                                U.S. Pat. No.                                                                          Date     Inventor   Title                                            ______________________________________                                        3,230,269                                                                               1/25/66 Nielsen    Vacuum Cleaner for                                                            Automobiles                                      4,405,158                                                                               9/20/83 Huberman   Air Filler Adapter                               4,053,962                                                                              10/18/77 McDowell   Suction-Cleaning                                                              Dust Retriever                                   4,114,230                                                                               9/19/78 MacFarland Deflator-Inflator                                                             Attachment                                       4,476,607                                                                              10/16/84 Ross       Portable Vacuum                                                               Cleaning Device                                  4,479,281                                                                              10/30/84 Mikutowski Method and Apparatus                                                          for Cleaning Phono-                                                           graph Records                                    4,506,406                                                                               3/26/85 LaMonte    Attachment Tool for                                                           a Vacuum Cleaner Hose                            4,688,295                                                                               8/25/87 Starnes    Vacuum Cleaner                                                                Attachment                                       4,694,529                                                                               8/22/87 Choiniere  Suction Device                                   ______________________________________                                    

The patents above evidence adapters or extension devices for vacuumcleaners in which the tool bore diameter is considerably less than thatof the tube connection to the vacuum cleaner tubular air inlet on thesuction side or the positive air pressure discharge on the outlet sideof the vacuum cleaner.

Huberman and McDowell lack the provision for air flow other than thatthrough the small diameter axial port on the small tube side of theadapter.

Choiniere employs a large oval opening within the bottom wall of theadapter. Further there is an elongated slot within the adapter tipadjacent to a hole therein. However, the purpose is not to increase theair flow to protect a vac motor but to provide two suction areas withinthe end and bottom of the blade.

In Nielsen, an elongated slot within the end of a flat flared nozzleprovides the primary suction opening for a mini sized vacuum cleaner, inthis case attachable to the intake manifold of an automobile engine. Theexistence of perforations within upper and lower walls permit additionalair flow through the adapter but in Nielsen, there is no vacuum cleaneror vacuum cleaner motor needing protection.

Starnes is representative of a tool having a tube diameter correspondingto the hose size of the conventional vacuum cleaner and coupled to theintake. The attachment facilitates cleaning of narrow spaces betweenfurniture pieces and employs narrow elongated brush elements on the endof the tube or alternatively, a further annular cleaning brush with ahollow end bearing the brush bristles and presumably an axial bore.

The prior art known to the applicant teaches adapters for supportingsmall diameter tools, with the adapters including a larger diametertubular portion for coupling to a conventional vacuum cleaner hose ordirectly to the vacuum or positive air pressure ports of a conventionalvacuum cleaner.

It is therefore a primary object of the present invention to provide animproved miniature vacuum tool adapter or attachment converter providingdramatic increase in air flow by attachment to a large size domestic orcommercial vacuum cleaner which insures prolonged air flow which reducesthe possibility of clogging, which insures air flow adequate to preventoverheating of the vacuum cleaner motor and in which the total air flowthrough the vacuum cleaner may be readily adjusted by varying the sizeof supplemental openings within the adapter itself.

SUMMARY OF THE INVENTION

The invention is directed to a vacuum cleaner adaptor for a micro toolfor a vacuum cleaner employing an air cooled or air pass through motorfor the prevention of overheating of the vacuum motor during operation.The adaptor comprises a tubular assembly adaptor or body consisting of alarge diameter tube section for attachment to the suction or positiveair pressure side of the vacuum cleaner, a small diameter tube sectionsized to the micro tool and an integral transition section connectingthe large diameter section to the small diameter section. One of theadaptor body sections comprises a plurality of air flow ports opening tothe interior of the adaptor and a shield movably mounted on the sectioncarrying the plurality of ports for movement between a first position inwhich the ports are fully open to air flow between the interior and theexterior of the adaptor body section and a second position in which theports are partially closed off to the air flow thereby ensuringprolonged air flow adequate to prevent overheating of the vacuum cleanermotor. The transition section between the adaptor body large diameterand small diameter sections is preferably of conical form with the airports comprising circumferentially spaced slots Within the conical formsection. The movable shield may constitute a conical memberconcentrically mounted on the adaptor body in flush contact with theconical section of the body and having circumferentially spaced slots ingeneral longitudinal alignment with the slots within the adaptor bodyconical section. Means are provided for mounting the conical shield forlimited rotation relative to the adaptor body to shift the shield from aposition where the slots are in axial alignment to one where the slotsare offset to reduce the air flow therethrough. A stop ring may beconcentrically mounted about the small diameter section of the adaptorbody with one end face in radial abutment with the conical shield tomaintain the conical shield surface in contact with the exterior of theconical section of the adaptor body. The adaptor body small diametersection may include a plurality of radially projecting abutmentsprojecting outwardly from the outer surface thereof towards the radiallyinner surface of the shield a small diameter portion. The shield smalldiameter portion may include a like number of radially inwardly directedprojections on the inner diameter thereof facing the outer periphery ofthe adaptor body small diameter section and being spaced radiallytherefrom to form arcuate gaps between the abutments, the width of whichgaps permit rotation of the shield member over an angular extent betweena first position where the slots of the shield and the adaptor body arein full alignment for maximum air flow and a second position where theslots are circumferentially offset for reduced air flow therethrough.

In another embodiment, the large diameter section of the adaptor bodymay include a radially projecting rib intermediate of the ends thereofand a radially projecting end wall proximate to the transition section,axially spaced from said rib and defining a circumferential recessbetween the rib and the radially projecting end wall. The shield mayconsist of a semicircular cylindrical section of solid sector shapehaving an inner diameter slightly in excess of the outer diameter of theadaptor body recess and being concentrically mounted thereto withopposite ends in abutment with the radial rib and radially enlarged endwall, respectively. The multiple air flow ports may comprise a pluralityof holes within the adaptor body large diameter section at the recess.oblique to the axis of the adaptor body and in a circumferential arrayswhereby rotation of the sector shape shield selectively closes off theoblique holes to vary the rate of air flow through the adaptor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the vacuum cleaner adapter for a microtool forming a preferred embodiment of the invention coupled to thesuction port of a domestic vacuum cleaner at one end at the other end bya small diameter tube to such micro tool:

FIG. 2 is an axial, sectional view of the adapter of FIG. 1;

FIG. 3 is an enlarged, perspective view of the adapter of FIG. 2;

FIG. 4 is an end view of the adapter of FIGS. 1-3 inclusive;

FIG. 5 is a perspective view of an adapter forming a second embodimentof present invention under full power conditions; and

FIG. 6 is a perspective view similar to that of FIG. 5, with the adapterat half power.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1-4 inclusive, a vacuum cleaner micro tool adapterforming a preferred embodiment of the invention is indicated generallyat 10, and is shown as being coupled at one end by a tubular coupling 12to a suction port 14 of a domestic vacuum cleaner indicated generally at16. The other end of the adapter 10 is coupled via a small diameterflexible hose or tube 18 to a micro tool indicated generally at 20.

The opposite end of the vacuum cleaner 10 to the rear of handle 22 onhousing 26 is provided with a positive air discharge port (not shown) ofa diameter equal to that of the suction port 14. The suction port 14 isformed by an axially projecting short length cylinder projectingoutwardly of front wall 24 of vacuum cleaner housing 26. The suctionpart 14 orifice is of standard 11/4 inch diameter. The tubular, malecoupling 12 takes the form of a short length (several inches) plastictube having an outer surface which is beveled inwardly from its axialcenter in opposite directions, i.e., tapered towards its opposite endsso as to permit one end to be frictionally inserted into the orifice ofthe large diameter cylindrical coupling section 30 of adapter 10 and theother within the suction port 14 orifice.

The adapter 10 of FIGS. 1-4 inclusive and adapter 10' of FIGS. 5 and 6form two separate embodiments of the invention and each adapter takesthe form of an adapter body and includes three major sections; a largediameter cylindrical coupling section, a conical transition section, anda small diameter cylindrical coupling section.

For the first embodiment 10, adapter body 29 includes a large diametercylindrical coupling section 30 having a bore 32 which is preferably11/4 inch in diameter for standard connection to a domestic orcommercial vacuum cleaner hose or suction port (such as port 14 of thevacuum cleaner 16, FIG. 1). The open end 30a of the large diametercylindrical section 30 receives the tapered external surface 28a of themale coupling 12, FIG. 1. The large diameter cylindrical section 30connects integrally to a small diameter cylindrical coupling section 34via a unitary conical transition section 36. All of the components ofadapter 10 may be formed of molded plastic such as Polyvinyl Chloride(PVC). In that respect, the conical transition section 36 of body 29functions as one element of a valve section indicated generally at 39,the other element of which is a rotatable shield indicated generally at38. FIG. 2. The rotatable shield 38 is a frustro-conical molded plasticmember having a conical portion 40 integrally molded to a large diametercylindrical portion 42 at one end, and a short length, small diametercylindrical portion 44 at the other end. The inner diameter of the largediameter cylindrical portion 42 is slightly larger than the outerdiameter of cylindrical section 30 of the adapter body 29 supporting theshield 38. In turn, the inner diameter of cylindrical portion 44 of therotatable shield 38 is slightly larger than the outer diameter of thecylindrical section 34 of the adapter body 29. The angulation of theconical section 36 of body 29 matches the angulation of the conicalportion 40 of the rotatable shield 38. The adapter body 29 and therotatable shield 38 are essentially in surface contact.

The large diameter cylindrical section 30 of the adapter body 29 isprovided with an integral, radially projecting rib 46 adjacent to end42a of the large diameter cylindrical portion 42 of the rotatable sheet38. The small diameter section 34 of the adapter body 29 is provided onits outer surface 34a, with a number of annular grooves 48, 50 which arelongitudinally oblique, of increasing depth from left to right andtowards the open end 34b of the small diameter adapter body section 34.An elastic plastic tube or hose 18 is sized such that its inner diameteror bore 52 is slightly smaller than the outside diameter of section 34of the adapter body and the flexible plastic tube 18 is force-fittedonto the outer peripheral surface 34a of the small diameter section 34.Edges 54, 56 formed by the oblique grooves 48. 50 function as barbs forpermitting the tube 18 to be force-fitted onto the end of the smalldiameter section 34 of the body but resisting removal of tube 18. Meansare provided for maintaining the axial position of the rotatable shield38, while permitting limited rotation of the shield concentrically aboutthe adapter body 29.

The conical transition section 36 of the adapter body 29 is providedwith a plurality (four) of elongated arcuate slots 60 atcircumferentially spaced positions, which slots 60 taper inwardly fromthe inner wall 36a of the transition section to its outer wall 36b. Theouter periphery of the large diameter cylindrical portion 42 of therotatable shield 38 forming with adapter body 29, air release valve 39,is knurled at 62 to facilitate hand rotation of the movable shield 38relative to the adapter body 29. Similar sized and numbered arcuateslots 64 are formed within the rotatable shield 38 conical portion 40,at common radial positions with body 29 corresponding to slots 60. Theslots 60. 64 of respective members are such as to be perfectly alignedin full open position of the air release valve 39.

Rotation of the air release valve 39 over a limited arcuate path resultsin misalignment of slots 60. 64 and partial closure of slots 60 toreduce the air flow passing through slots 60 64. Stops are provided atthe small diameter portion sections 34 of the body 29 and small diameterportion 44 of the rotatable shield 38. As may be seen by reference to

FIGS. 2 and 4, which is a sectional view of FIG. 2 taken about line4--4, the small diameter portion 44 of the rotatable shield 38 isprovided with radially inwardly directed projections or tabs 66 from theradially inner wall 44a of the small diameter portion 44 of therotatable shield 38.

The small diameter cylindrical portion 44 of the rotatable shield is ofa short axial length and terminates in a radial end wall 44b. Fixedlymounted to the exterior of the small diameter cylindrical section 34 ofthe adapter body 29 is an annular stop ring 45 having an inner diameteron the order of the outer diameter of the cylindrical section 34 of body29. Further, the small diameter section 34 of body 29 is provided with apair of longitudinally spaced circumferential ribs 34c of semicircularcross section which project radially outwardly of the small diametersection 34. The stop ring 45, which may be formed of a resilientplastic, rubber or the like, is provided with matching semi-circularcross sectional grooves 68 which receive the radially projecting ribs34c to axially lock the stop ring in a position where radial end face45a of the stop ring abuts radial end face 44b of the rotatable shield38. This maintains the surface contact between the conical portion 40 ofthe rotatable shield and the conical section 36 of the adapter body 29.

In addition to ribs 34c, the adapter body 29, at the juncture betweenthe conical section 36 and the small diameter section 34 of that member,is provided with radially outwardly projecting arcuate abutments 70which are of a radial height so as to terminate just short of contactwith the inner wall or bore 44a of the small diameter cylindricalportion 44 of the rotatable shield 38. There are four abutments 70corresponding to the four radial projections 66 of the rotatable shield38 and the abutments 70 are angularly oriented so as to occupy aposition between adjacent projections 66, see FIG. 4. Additionally, theabutments 70 extend circumferentially approximately 50° leaving a radialgap 72 between the end face of one abutment and the end face of theprojection to the opposite side of the gap 72, while the opposite radialend face of the abutment 70 is in contact with a radial end face of theother radial projection 66, between which a given abutment 70 islocated.

As shown in FIG. 4, by rotation of the rotatable shield 38 from theposition shown in FIG. 4 which is the closed position for the airrelease valve 39 with maximum circumferential misalignment between slots60 and 64, the radial projections 66 rotate counterclockwise with radialface 66b of projections 66 moving away from radial end face 70a of eachabutment 70, while each outer projection 66 has its radial and face 66amoving into contact with radial end face 70b of a corresponding abutment70. The extent of rotation is therefore about 25° from full openposition of the air valve to partial open position. The angularmisalignment between ports 64 of the air valve movable shield 38 andports 60 of adapter body 29 may be seen by the dotted line position ofport 64 of the movable shield 38. FIG. 4.

The air release valve 39 formed by components 38, 29 is in at leastpartially open position at all times to prevent overheating of thedomestic or commercial vacuum cleaner motor. Further, the air releasevalve 39 can be regulated by providing more openings, if desired, whenlarger motors are used as the power source for the domestic orcommercial vacuum cleaner. The stoppers or abutments 70 limit rotationof the rotatable (movable) shield 38 between the max open and near onehalf closed positions. The openings in the adaptor body are designed toaccommodate vacuum cleaners that have suction power measured in inchesof waterlift from twenty (20) inches to one hundred two (102) inches.With the slots of the adaptor body fully open enough passage of air isensured through the vacuum cleaner motor measuring the 102 inches ofwaterlift to prevent overheating of the motor. Preferably, the tube 18is a 5/16 inch hose section and is attached at its opposite end to anappropriate vacuum (or positive air pressure) operated tool such as tool20. Tool 20 is depicted as having a brush formed by a bristle section22a of annular form permitting vacuum pulling of particles dislodgedunder brush operation through the core of the annular brush 22a andthrough the bore of the small diameter plastic tube 18. Alternatively,if the hose section 18 is connected to the positive air pressure orblower side of the domestic or commercial vacuum cleaner 26 (not shown).the hose section can be directed to confided areas to blow out dust ordebris with or without the tool 20 (brush) attached to the free end ofthe small diameter tube 18 remote from its connection to adapter 10.

Since the adapter 10 can be attached to virtually any vacuum cleanerwhich uses attachments, it provides an opportunity for use of bothdomestic and commercial vacuum cleaners with attachments to safelyconvert their vacuum, for use with a miniature vacuum attachment set.Work may be accomplished in confined areas such as photo equipment,computers, arts and crafts, office machines, stereo equipment, householduse, tape decks, machining, hobbies, jewelry, keyboards, lenses,electronic turntables and the like. The adapter or miniature vacuumattachment converter 10 safely converts any domestic or commercialvacuum cleaner that uses attachments for use with miniature attachmentssuch as the tool 20 illustrated in FIG. 1. The air flow (CFM) isdramatically increased through the miniature attachment because of thenature of the power source, the receptacle for retaining the collecteddust is dramatically increased over a standard miniature vacuum cleaner.The size of the dust receptacle also prolongs the air flow sinceminiature battery operated vacuum cleaners have a minuscule dustreceptacle that can clog easily and can reduce air flow to almost zeroin a short period of time. By using the adapter 10 of this inventionwith a full size vacuum cleaner, the power source if uniform overprolonged use of the adapter and its tool.

FIGS. 5 and 6 illustrate a second embodiment of the invention. In thisembodiment, adapter 10' takes the form of an elongated molded plastictubular body indicated generally at 129 and includes, integrally, alarge diameter cylindrical coupling section 130 from which projectsradially outwardly, an annular rib 180 intermediate of its ends. Aradially enlarged end at 182 forms with rib 180, an annular peripheralrecess 184 therebetween. The adapter body 129, similar to the firstembodiment, includes integrally a conical transition section 136 withthe large diameter cylindrical coupling section 130. Section 136terminates at the side opposite section 130 in a reduced diametercylindrical coupling section 134. Tube 18 attaches to the small diametercylindrical coupling section 134 in the same manner as the firstembodiment, and the balance of the assembly shown in FIG. 1 with adapter10' is employed in use as depicted in FIG. 1.

A rotatable shield indicated generally at 138 is provided, ofcylindrical form. Shield 138 is sector shaped, that is, it is not acomplete cylinder having longitudinal end faces 198 and 200circumferentially spaced approximately 90°. The balance of the rotatableshield 138 is of a solid cylindrical form defined by opposite axial endfaces 196 and oppositely tapered or oblique outer side wall sections190, 192 from an axial center line 194 extending circumferentially aboutthe shield 138. The rotatable shield 138 forms, in conjunction with thelarge diameter cylindrical coupling section 130 of body 129, an airrelease valve 139.

In that respect, circumferentially spaced and longitudinally spacedholes 160 pass through the wall of section 130. The holes 160 are inlongitudinal rows, side by side with the holes being drilled orotherwise formed oblique to the axis of body sections 130 rather thanradial. Holes 160 are directed obliquely towards the small diametercylindrical coupling section 134, from the inside surface of tubularadapter body section 130 towards the outside surface of recess 184 ofthe body section 130. If the holes 160 were radial, the holes tend tocreate an extremely undesirable noise when air is being passed through aconfined area. By oblique angling the air holes or openings 160 to theaxis of the body section 130, a number of degrees from radial, the noisereduces dramatically when the tool employed with the adaptor 10' is inoperation with the cylindrical coupling section 130 coupled to a hosesection of the vacuum cleaner 16, FIG. 1, or directly to a port such assuction port 14 (or the positive air pressure blower port thereof (notshown)).

In FIG. 5, all twelve holes 160 are open and the adapter 10' issubjected to full power, with maximum flow passing over or through thevacuum cleaner motor.

By rotating the rotatable shield from the position shown in FIG. 5 tothe position shown in FIG. 6, all twelve holes are completely coveredsuch that the air flow to the cooling motor is reduced 1/2 by uncoveringsix similar holes 160, in a set circumferentially shifted by near 180°and the system is under half power.

Advantageously a stop or bar 186 is fixedly mounted within recess 184,having opposite ends of the bar 186a, 186b abutting and adhesively fixedor otherwise mounted, respectively to end walls of rib 180 and theradially enlarged end 182 of the adapter body 129. By locating at givencircumferential position, the fixed stop or bar 186, the rotation of theshield 138 may be limited so that the shield 138 is rotatable onlybetween two extreme positions, one in which all twelve of the one set ofholes 160 are uncovered and the second, where only six of the holes 160of a second set are open to the atmosphere, with the balance of thetwelve holes 160 effectively covered and blocked by the imperforatecylindrical shield 138 as per FIG. 6.

While the description above is to preferred embodiments and containsspecific parameters and location and connection details these should notbe construed as limitations of the scope of the invention and the systemand the adapter as illustrated in the drawings are exemplary only. Thescope of the invention is determined not by illustrated embodiments, butby the dependent claims and their legal equivalents.

I claim:
 1. A vacuum cleaner adaptor for a micro tool for a vacuumcleaner employing an air cooled or air pass through motor for preventingoverheating of the vacuum cleaner motor during operation, said vacuumcleaner including suction and positive air pressure sides passing airflow over or through said vacuum cleaner motor, said adaptor comprisinga tubular assembly including an adaptor body having a large diametertube section for attachment to the suction or positive air pressure sideof the vacuum cleaner, a small diameter tube section sized to the microtool for coupling thereto, and an integral transition section connectingthe large diameter section to the small diameter section, one of saidadaptor body sections comprising a plurality of air flow ports openingto the interior of the adaptor, and a shield rotatably mounted on saidsection carrying said plurality of air flow ports for rotation between afirst position in which the ports are open to air flow between theinterior and exterior of said adaptor body section, and a secondposition in which said ports are partially closed off to said air flowand said adaptor further includes stop means for limiting movement ofsaid shield to rotation between said first and second positions therebyinsuring prolonged air flow through said tubular assembly for passagethrough or over said motor adequate to prevent overheating of the vacuumcleaner motor with the rate of air flow through the vacuum cleaner beingreadily adjustable depending upon the nature of the micro tool attachedthereto.
 2. The adaptor as claimed in claim 1, wherein, said transitionsection between said large diameter and said small diameter sections ofsaid adaptor body is of conical form, wherein said air ports comprisecircumferentially spaced slots within said conical form section, andsaid movable shield comprises a conical member concentrically mounted onsaid adaptor body in flush contact with said conical section of saidbody, and having circumferentially spaced slots in generallylongitudinal alignment with the slots within said adaptor body conicalsection and means for mounting said conical shield for limited rotationrelative to said adaptor body to shift said shield from said firstposition where said slots are in axial alignment and said secondposition where said slots are offset to reduce the air flow through saidslots for varying the air flow through said adaptor during vacuumcleaner operation of said micro tool.
 3. The adaptor as claimed in claim2, wherein said shield is concentrically mounted about the exterior ofsaid adaptor body, and said adaptor further comprises a stop ring,concentrically mounted about the small diameter section of said adaptorbody, having an end face in radial abutment with said conical shield andmaintaining the conical shield in surface contact with the exterior ofthe conical section of said adaptor body.
 4. The adaptor as claimed inclaim 3, wherein said adaptor body small diameter section includes atleast one radially projecting rib on the outer surface thereof, andwherein said stop ring includes an angular groove on the inner peripherythereof sized to and receiving said radial projection for locking saidstop ring axially on said adaptor body small diameter section.
 5. Theadaptor as claimed in claim 2, wherein said movable shield comprises atubular member, mounted concentrically about said adaptor body, andincluding in order and integrally a large diameter portion having aninner diameter slightly larger than the outer diameter of said largediameter section of said adaptor body, a conical body transition portionand an integral, small diameter portion having an inner diameterslightly larger than the outer diameter of the small diameter section ofsaid adaptor body, wherein said adaptor body small diameter sectionincludes a plurality radially projecting abutments projecting radiallyoutward from the outer surface thereof towards the radially innersurface of said shield small diameter portion, and wherein said shieldsmall diameter portion includes a like number of radially inwardlydirected projections on the inner diameter thereof facing the outerperiphery of said adaptor body small diameter section and spacedradially therefrom, and wherein, said radial projections of said shieldmember and said radial abutments of said adaptor body are angularlyoffset, so positioned and of such arcuate widths such that arcuate gapsare created therebetween permitting rotation of said shield member overan angular extent of said gaps between positions where the slots of saidshield and said adaptor body are in full alignment for maximum air flowtherethrough and wherein, said slots are circumferentially offset forreduced air flow.
 6. The adaptor as claimed in claim 5, wherein saidcircumferentially spaced slots within said conical transition section ofsaid adaptor body taper inwardly in a direction from the interior ofsaid adaptor body to the exterior thereof and wherein, the arcuate slotswithin said shield member conical portion taper outwardly from the innersurface thereof to the outer surface thereof.
 7. The adaptor as claimedin claim 2, wherein said large diameter portion of the shield member isknurled on the outer periphery thereof for facilitating manual rotationof said shield about the longitudinal axis of the adaptor.
 8. A vacuumcleaner adaptor for a micro tool for a vacuum cleaner employing an aircooled or air pass through motor for preventing overheating of thevacuum cleaner motor during operation, said adaptor comprising a tubularassembly including an adaptor body having a large diameter tube sectionfor attachment to the suction or positive air pressure side of thevacuum cleaner, a small diameter tube section sized to the micro toolfor coupling thereto, and an integral transition section connecting thelarge diameter section to the small diameter section, one of saidadaptor body sections comprising a plurality of air flow ports openingto the interior of the adaptor, and a shield movably mounted on saidsection carrying said plurality of air flow ports for movement between afirst position in which the ports are open to air flow between theinterior and exterior of said adaptor body section, and a secondposition in which said ports are partially closed off to said air flowand thereby insuring prolonged air flow adequate to prevent overheatingof the vacuum cleaner motor with the rate of air flow through the vacuumcleaner being readily adjustable depending upon the nature of the microtool attached thereto and stop means for limiting said shield tomovement between said first and second positions, and wherein said largediameter section of said adaptor body includes a radially projecting ribintermediate the ends thereof, and a radially projecting end wallproximate to said transition section, axially spaced from said rib anddefining a circumferential recess therebetween, said shield comprises asemicircular cylindrical section of solid sector shape having an innerdiameter slightly in excess of the outer diameter of said adaptor bodyrecess, and being concentrically mounted thereto with opposite ends inabutment with said radial rib and said radially enlarged end wall, andwherein, said multiple air flow ports comprise a plurality of holeswithin said adaptor body large diameter section at said recess, obliqueto the axis of said adaptor body and in at least one circumferentialarray whereby, rotation of said sector shape shield selectively closesoff said oblique holes to vary the rate of air flow through saidadaptor.
 9. The adaptor as claimed in claim 8, wherein aid oblique airflow holes, are longitudinally and circumferentially spaced to form aseries of longitudinal rows of said holes which rows are selectivelyclosed off by rotation of said shield of sector shape.
 10. The adaptoras claimed in claim 9, wherein said stop means comprise at least onestop bar fixedly mounted within the recess of said adaptor body largediameter section and having opposite ends abutting at said rib and saidlarge diameter end wall for limiting rotation of said sector form shieldto limit closure of said holes extending obliquely through said largediameter section for ensuring adequate flow of cooling air to saidvacuum cleaner motor during operation of said micro tool.